I think NP, New Process, change the syncro assemblies 3 times in the production NP 833 4 speed Mopar tranny from 1964 up to the last change in 1970, maybe more or less confused
I have seen three different types of synchro assemblies in those trannies, The later ones shift a lot better than the earlier ones did up

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)